I want to share that I found a solution to the backlight problem. The forum previously answered how to deal with a complex model, but the topic is incorrectly named, so it’s hard to find: Hightlayer issues
It would be nice if someone adds examples to the documentation (here Highlighting Meshes | Babylon.js Documentation ) on how to deal with highlighting in complex models (and instances at the same time):
Complex model: Babylon.js Playground (from this thread: Hightlayer issues)
Instaces: https://playground.babylonjs.com/#AHP3J7#8 (from this thread: Why can't I add an InstancedMesh to HighlightLayer - #7 by kekeqy)